SummaryThe traditional account of micro‐reductive explanations, in terms of bridge‐law derivations and attribute‐identities, is subjected to critical analysis. Formal expositions of this approach especially those of R. L. Causey, are shown to have oversimplified certain relations between micro‐parts and wholes, and between identities and explanations, and to have neglected a key difference between homogeneous and heterogeneous micro‐explanatory contexts. An alternative treatment of part‐explanation adequacy is outlined and illustrated.